Lots of videos having been hitting the web after Activision gave a first taste of MW2 multiplayer gameplay to outsiders at an event in Hollywood.

Game Trailers have many on the Modern Warfare 2 page.

However more interesting is picking apart the videos and seeing what weapons are on offer, attachments and perks.

Primary Weapons
Assault - M4A1, FAMAS, TAR-21, SCAR-H
Sub Machine Guns - MP5K, UMP45
Light Machine Guns - L86 LSW, RPD
Sniper Rifles - ?
Riot Shield - Shield

Secondary Weapon
Machine Pistols - PP2000, G18
Shotguns - SPAS 12, AA-12
Handguns - Colt .44 Magnum, USP45
Launchers - AT4, M79 "Thumper"

Equipment
Frag
Semtex
Throwing Knife
Tactical Insertion
Blast Shield

Attachments
Red Dot
Grenade launcher
Silencer
Shotgun
Heartbeat Sensor

Perks
Tier 1 - Sleight of Hand, Bling, Marathon, Scavenger
Tier 2 - Stopping Power, Lightweight, Cold-blooded, Hardline
Tier 3 - Commando, Steady Aim, Scrambler
Death Streaks - Copycat, Painkiller

Kill Streaks
3 Kills - UAV
4 Kills - Care Package
4 Kills - Counter UAV
5 Kills - Sentry Gun
5 Kills - Predator Missile
6 Kills - Precision Air Strike
7 Kills - Strike
7 Kills - Attack Helicopter
8 Kills - Emergency Airdrop
9 Kills - Pave Low
9 Kills - Stealth Bomber
11 Kills - Chopper Gunner
11 Kills - AC-130
15 Kills - EMP
25 Kills - Tactical Nuke